Get a single sales invoice

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the agent knows it's safe. The description adds 'including all line items' which is useful context about the response content. No mention of potential errors or prerequisites, but annotations cover the key behavioral traits.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences, efficient. The repeated phrase 'Get a single sales invoice' appears twice (first line and second line), which is slightly redundant. But the structure is clean and front-loaded with the core purpose.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple GET-by-ID operation with rich annotations and 100% schema coverage, the description is adequately complete. It doesn't describe response format, but no output schema is present; still this is a basic retrieval tool, and the description covers the essential behavior.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so both parameters are already documented. The description says 'by ID' reinforcing the id parameter but adds no new detail about admin parameter. Baseline 3 is appropriate when schema covers everything.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Description clearly states 'Get a single sales invoice' with specific verb and resource, and adds 'by ID, including all line items' for specificity. It is distinguishable from sibling list_sales_invoices and update_sales_invoice, though doesn't explicitly name them.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies when to use: when you need a single invoice by ID. No explicit exclusions or alternatives are mentioned, but the 'Get' verb and ID requirement make it straightforward. Sibling tools exist but no comparison is provided.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.